Scratched Film

[chris_raney1]

<p>My M4-P appears to be scratching my film. When I look at my negatives under indirect light with my loupe I see several lateral bands that have appeared in my prints. Just tonight I had to shelve a negative because of one particularly long line that was maddeningly visible in a large patch of shadow detail.</p>

<p>I've been making small, resin coated snaps for my students, so I've been able to ignore this problem. And sometimes it doesn't seem to appear in my prints. But close inspection of all of my negatives out of this camera reveal these long scratches. From what I can see these bands don't appear in my scanned negatives. But now that I'm energized into making some serious, fiber-based prints once again I have this problem staring me in the face.</p>

<p>I don't bulk load, and I never open a plastic film bottle until I'm ready to load film. And the film I've retrieved from the camera always gets snapped into the empty bottle. I open my film cassettes with a bottle opener and load my film reels in the darkroom. My only contact with the film is on the edges. </p>

<p>I shoot Tri-X exclusively. Is it possible this is a manufacturing problem? I know this appears extremely unlikely, but wouldn't running film through a camera for years have the effect of honing down whatever places in the camera the film contacts?</p>

<p>No doubt I'm looking at another expensive tear-down and a CLA to boot? I just sent this camera off last year for a CLA and a minor repair (someone in LA, I believe).</p>

[bob_sunley]

<p>Run a film part way thru, open the back and mark the film at the edge of the film canister. Remove the film and examine for scratches. With the reference mark on the film you should be able to determine the location of the "scratch generator" in the camera. It also might be easier to spot the scratches if you clear the film in fixer if you can't spot them on the film. It doesn't take much to scratch the emulsion or the substrate. If you want you can open the camera in the darkroom and process the film before examining. It's also possible the film is being scratched during rewinding.</p>

<p> </p>

[chris_raney1]

<p>I'm not sure how your suggested technique would work, Bob. Since it's a Leica once that film cassette is in the camera it's not coming out until the film is rewound, so I wouldn't know where in the process the film's being scratched: on the advance or the rewind. </p>

<p>I suppose I need to do a side-by-side comparison with a roll of film right out of the box. I can cap the lens and run a roll through the camera, then develop it along with that virgin roll. But I'm sure not having exposed emulsion to contrast against the scratches wouldn't be of much help in determining the problem, but I'll try it.</p>

<p>I'm printing with an old Omega D-2 with a condenser head and a filter drawer. I know that cold light heads will often diffuse dust and scratches, and I actually have an equally old Omega cold light head for this enlarger; but I do need that filter drawer. Hey, I just thought of something: I could try placing the filter atop the negative carrier and see if that worked. </p>

<p>Thinking out loud here. I just wish this were a problem I could solve with my Dremel and an emory wheel!</p>

 

[mukul_dube]

<p>Scratches ought not to show up as <em>bands</em>.</p>

[will_wright1]

<p>I have a vintage Contax 1 that was a BAD scratcher. I took some extremely fine jewelers rouge paper and gently rubbed the pressure plate which knocked down some digs in the plate and then cleaned it with alcohol. Finally I q-tipped some teflon lubricant on the plate itself and it's now slick as a whistle and a non scratcher. Or...first simply carefully clean your pressure plate with alcohol. </p>

[lex_bosman1]

<p>Are you sure it is the camera that makes the scratches? I thought my M4-2 did that too, until I found it occasionaly on film with other M's as well. Turned out it was the scanner or the developer at the firm where I had my films developed ans scanned. A CLA of the M4-2 showed there was nothing wrong with it. But a tiny grain of dust can ruin a film indeed.<br>

Lex</p>

[chris_raney1]

<p>They're not exactly bands, Mukul. I probably misstated what I meant. But there are several absolutely straight, tiny scratches that go across the negative. Actually, there are over a dozen of these lines, and looking at that offending negative I attempted to print last night these scratches extend across the entire 5-shot negative strip; and as a consequence across the entire five feet of film! And no, Lex, My scanner is not causing this problem, because this phenomenon exists on strips of negatives I haven't scanned. I have an 8x loupe that confirms this damage is physical.</p>

<p>So, Will. You think maybe it's the pressure plate that's leaving these scratches on the backside of the film? That would make sense, though I had convinced myself it was on the emulsion side. I like your technique, but I'm afraid if I buff off any anodizing layer from that plate I'll cause reflections problems on the negatives. I will definitely look in to the Teflon lubricant, though.</p>

[paul_wheatland]

<p>Occasionally a film chip will cause problems especially in a botton loader camera. I have successfully "swept" out chips very carefully with a clean crisp business card. You do so at your own risk, as this is merely my experience!</p>

[notraces]

<p>Chris - I had a very similar issue not long ago. It happened to be with my M4P, too. I was getting the line(s) you're describing here - but I thought maybe I just had a piece of dirt caught in the light trap of the film canister. Thankfully, it was on a roll I didn't much care about -- but then it happened again on a roll I DID care about. I scanned both rolls and super imposed them over each other - and the line was pretty much in the same spot. So - I blew out the camera with air - and made sure the back plate was clean and checked for rough edges. I had just had the camera CLA'd - so I was sure it was just something caught up somewhere.<br>

<br /> I loaded another roll of film and ran about 5 frames of nothing -- opened the back to inspect the area where I know the line would be - and sure enough it was there again - and stopped - the rest of the roll was clean as I would expect.<br>

<br /> I did a little research on the subject and found some older threads - maybe it was even here on photo.net - describing similar issues with the M4P and older M6 Classics. The issue was in the back plate - but it wasn't clear as to what the issue was - it just referred to previous posts that I couldn't find reference to.<br /> I sent a note off to my Leica repair person - Sherry Krauter - and she just told me to send it in along with a strip of the offending negative.<br>

<br /> Not long after I received my camera back - she replaced the back plate (included the old one in the package) - and I've not seen the problem since.<br>

<br /> Now -- that being sad - I did notice I was getting other linear scratches from rolls I shot with my M7 -- but they were not consistent. Long story short - I found that the SA-21 feeder on my Nikon 5000 was causing the scratches. I figured this out by scanning a few frames - and seeing the scratches - and then ejecting the frame and seeing that the other frames (that didn't go through the scanner) remained unscathed. I also have another feeder - so I tried it out and the scans came out clean. So -- I need to send the SA-21 in for repair and cleaning.<br /> Hope this helps.</p>

[Troll]

<p>Are the scratches in the emulsion or the film base?</p>

[chris_raney1]

<p>I'm not sure, Bill. But Will and Bob have given me hope that I might solve this problem easily and cheaply!</p>

[Dieter Schaefer]

<p>Maybe I have missed something when reading the responses. Should be fairly easy to determine if it is the backplate or not. Load film, take a few shots, then open the back, mark the film, take a few more shots, mark the film, close the back, take a few more shots, then take the film out (rewind with the back open). Examine the film and if there aren't any scratches when the backplate was not in contact with the film, then you've got your answer.</p>

 

[steve_larese1]

<p>Run a cotton ball or Q-tip over the rails, plate, etc. to see if there are any snags. Once IDed, you may be able to correct the problem.</p>